Alisha Walker, 20, of Ohio, was extradited from Indiana on Wednesday in the murder of Filan. Alisha Walker who's accused of being a prostitute is charged with killing him after they met on the internet

"The defendant in a videotaped statement to authorities, claimed the victim grabbed a knife which the defendant was able to grab control of and stabbed the victim 13 times," John Dillon, Cook County State's attorney, said. "Officers also observed bloody footprints that appeared from a high heel shoe of a woman from the victim's body to the victim's front door."

Police say Walker has a history of prostitution, and Filan contacted the woman online to perform a sex act for money. Last week, police tracked Walker down in Fort Wayne, Indiana, through her cell phone because Filan had sent her text messages, officials said.

Walker's court-appointed attorney had no comment. Her family said she acted in self defense.

Filan taught at Brother Rice High School in Chicago for nearly 40 years.